Natural Water Cycle

Did you know that we have always had the same water on earth? We could be drinking the same water that dinosaurs once drank. Water constantly moves through a natural cycle of evaporation, condensation and precipitation which cleans water and allows it to move around the earth.

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about the Natural Water Cycle

Evaporation

Heat from the sun provides the energy for water to change from a liquid, like we drink, into a vapour. There is almost always water vapour in the air around us, but we can’t see it. On a hot, sunny day water will evaporate faster than on a cold, cloudy day.

We can see the process of evaporation in the ocean but evaporation happens everywhere there is water, even in your washing! When you hang your clothes out on the washing line the sun evaporates the water, which forms part of the water cycle.

Condensation

When water vapour cools, it condenses back into tiny droplets of liquid water. These droplets are small enough to float in the air and eventually collect together to make a cloud. Clouds can be blown by the wind to move water to different parts of the earth.

Just as hot air rises, so do vapours, but as the vapours cool down they physically change from a gas state to a liquid state. As they get colder they band together and eventually they condense so much they form clouds.

Precipitation

As more and more water droplets form, they will join together to form bigger water drops in the clouds. These drops become too heavy to stay in the air and will fall to earth as rain. If it is very cold, the water might freeze and fall as hail or snow. Any water that falls from the sky - rain, hail or snow - is called precipitation.

As the clouds get filled with water particles, eventually gravity kicks in and the rain starts to fall. Depending on the temperature of the atmosphere the water may fall from the clouds in the form of rain, snow or sleet.

Runoff

Some precipitation will soak into the ground or be taken up by plants but the rest will runoff into streams, rivers, lakes and make its way to the ocean.

Not all water goes straight back into the rivers and ocean, sometimes it soaks deep into the ground and collects in cracks or pores in the rock. We call this water groundwater and it will eventually flow into our rivers, lakes or the ocean.

Waterways

Any rubbish or pollution left on the land can be washed into our waterways. This can cause problems for animals and plants that depend on these waterways and ultimately affect the water that we drink.

And the cycle starts again

The sun and wind will cause water that has collected as runoff to evaporate and the natural water cycles starts again. Now here comes the sun again...